earthquakes

=Earthquake=

From Wikipedia, the free encyclopedia
//This article is about the natural seismic phenomenon. For other uses, see [|Earthquake (disambiguation)].////"Quake" redirects here. For other uses, see [|Quake (disambiguation)].// An **earthquake** (also known as a **quake**, **tremor**, or **temblor**) is the result of a sudden release of energy in the [|Earth's] [|crust] that creates[|seismic waves]. Earthquakes are recorded with a [|seismometer], also known as a seismograph. The [|moment magnitude] (or the related and mostly obsolete [|Richter] magnitude) of an earthquake is conventionally reported, with magnitude 3 or lower earthquakes being mostly[|imperceptible] and magnitude 7 causing serious damage over large areas. Intensity of shaking is measured on the modified [|Mercalli scale]. At the Earth's surface, earthquakes manifest themselves by shaking and sometimes displacing the ground. When a large earthquake [|epicenter]is located offshore, the seabed sometimes suffers sufficient displacement to cause a [|tsunami]. The shaking in earthquakes can also trigger landslides and occasionally volcanic activity. In its most generic sense, the word //earthquake// is used to describe any seismic event — whether a natural [|phenomenon] or an event caused by humans — that generates seismic waves. Earthquakes are caused mostly by rupture of geological [|faults], but also by volcanic activity, landslides, mine blasts, and nuclear experiments. An earthquake's point of initial rupture is called its [|focus] or [|hypocenter]. The term [|epicenter]refers to the point at ground level directly above the hypocenter. http://en.wikipedia.org/wiki/Earthquake